Without limiting the scope of the invention, its background is described in connection with screwdrivers and related devices.
U.S. patent application Ser. No. 12/567,152 to Shiyu Sun discloses a screwdriver handle having a storage compartment comprising a connecting rod, a handle body and a rear cap connected in series. The connecting rod includes rod body, which is equipped with hollow plug hole inside, and the other end of the rod body is connected to the handle body. The handle body is provided with a storage compartment that can hold precision screwdriver and spare sleeve.
U.S. Pat. No. 4,114,663 issued to Brynley Viner (1978) discloses a screwdriver body including a tubular housing axially movable with respect to the remainder of the body. An automatic screwdriving and feeding apparatus has a screwdriver body with a tubular housing axially moveable thereon. Screw holding elements are mounted in the tubular housing and are resiliently biased inwardly, or are resiliently deformable, so as to hold a screw for driving. Drive means in the body can move axially relatively to engage the screw and apply rotary drive. Feed means supply screws one at a time to the screw holding elements.